Safely convert between []int and C.int*
Safely convert between []int and C.int*

Different golang implementations have different sizeof(int) -- so we
can't always pass []int to gdal simply with an unsafe pointer. Change it
so we allocate a []C.int, copy the values through the C.int constructor
for safe conversion, and pass a pointer to that.

helmi03/gdal,helmi03/gdal,ksshannon/gdal-go,foobaz/gdal,foobaz/gdal,lukeroth/gdal,lukeroth/gdal,ksshannon/gdal-go,bbradbury/gdal,bbradbury/gdal